Papillary renal cell carcinoma: a clinical, radiologic, and pathologic study of 34 cases.

Papillary renal cell carcinoma (RCC) is known by its tendency to avascularity by angiography; however, data concerning its clinicopathologic spectrum and prognosis are not available. In a review of 224 renal cell carcinomas accesioned in our files, 34 were found to be papillary and 190 of other histologic types. A comparative analysis of these two gropus revealed marked differences. The majority of papillary tumors (85.3%) were in pathologic stage I, whereas more than half of the nonpapillary tumors had extended beyond the limits of the kidney. Follow-up data revealed that the survival for papillary RCC was significantly higher than that for nonpapillary tumors. This difference held true even when tumors in the same pathologic stage were compared. Many papillary tumors, particularly those with a favorable course, were massively necrotic, densely infiltrated by macrophages, or both. In view of these findings, the possibility that host mechanisms are involved in destruction and confinement of the tumor is discussed. Examination of kidney tissue distant from the tumor disclosed, in some cases, atypical hyperplastic changes of collecting tubules; this raises the possibility that some papillary tumors arise from distal tubular epithelium. Hypo- or avascularity was present in all papillary RCC's studied by angiography.